New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/27775#discussion_r604341393

Comment:
openblas has:

```
case "${XBPS_TARGET_MACHINE}" in
	armv5*) make_build_args+=" TARGET=ARMV5" ;;
	armv6*) make_build_args+=" TARGET=ARMV6" ;;
	armv7*) make_build_args+=" TARGET=ARMV7" ;;
	aarch64*) make_build_args+=" TARGET=ARMV8 DYNAMIC_ARCH=1" ;;
	i686*) make_build_args+=" BINARY=32 TARGET=GENERIC DYNAMIC_ARCH=1" ;;
	x86_64*) make_build_args+=" BINARY=64 TARGET=GENERIC DYNAMIC_ARCH=1" ;;
	ppc64le*) make_build_args+=" TARGET=POWER8 DYNAMIC_ARCH=1" ;;
	ppc64*) make_build_args+=" TARGET=PPC970MP" ;; # dynamic arch broken for <power6
	ppc*) make_build_args+=" TARGET=PPCG4" ;;
	mips*) broken="Not supported" ;;
	*) broken="Add your CPU" ;;
esac
```

which would mean that eventual `riscv` target would be broken by default, for example, and would block octave from being built instead of building it with `lapack`. I think listing where it's known to work is a bit more correct.